How to prevent encoding plugin HTML output to entities?

Question

Someone asked me to create a solution to use HTML anchors () in the WP blog tagline. E.g. like:

Just another <a href="http://www.wordpress.org">WordPress</a> website

I came up with a small plugin where the user can use pseudo-code in the tagline, which is converted by the plugin to HTML anchors. Something like

Just another [[http://www.wordpress.org]]WordPress[[/]] website

This works fine, however WordPress keeps encoding the HTML to entities, and I have no clue how to resolve or prevent this.

My best guess is that some other filter hook fires after my plugin, and maybe I need to use some other hook(?) I tried option_blogdescription and pre_option_blogdescription and both have the same effect. However, this is just a wild guess and even then, I don't know whch hook to use then.

Also I tried diffent ways of getting the tagline content (To prevent that it already arrived as entities) I tried to receive it directly from the hook parameter, getting with get_option, getting with $wpdb->get_results but all with the same result.

And I tried several things to decode it like html_entity_decode() and wp_kses(). Again, all with the same result.

But if everything is encoded after my plugin comes in, none of my effort will have any effect.

I have more versions. Two of the latest:

The Hook add_filter( 'option_blogdescription', 'add_html_blog_description' );

Function 1

function add_html_blog_description( $option_value ) {
    $url = 'http://www.wordpress.org';
    $tagopen = '[[';
    $tagclose = ']]';
    $option_value = str_replace($tagopen, '<a href="' . $url .' ">', $option_value);
    $option_value = str_replace($tagclose, '</a>', $option_value);
    return $option_value;
} 

function 2

function add_html_blog_description( $option_value ) {
    global $wpdb;
    $allowed_html = array(
        'a' => array(
            'href' => array(),
            'title' => array()
        )
    );
    $results = $wpdb->get_results( "SELECT `option_value` FROM `wdwp_options` WHERE `option_name` = 'blogdescription'", ARRAY_A );
    $new_tagline = $results[0]['option_value'];
    $new_tagline =  html_entity_decode (wp_kses( $new_tagline, $allowed_html ) );
    return $new_tagline;
}

Answer 1

With all credits and many thanks to Jacob Peattie in the comment above. After Jacob's remark that the title is used for e.g. the title element and by some plugins, I followed his advice to create a new field because he made me realize that the front page tagline needed somehow to be seperated from the other places where the description is being used.

So I created a custom field in the WP settings, a function to (only) allow HTML for HTML anchors (All other code keeps decoded to entities) and a function to parse the alternative tagline.

Then the new function needed to be implemented in the theme, so I created a child theme with the new alternative tagline in header.php

So not a simple plugin as I hoped for, but a child theme with all good reasons :) And it works like a charm. Thanks Jacob!